Cottocomephoridae
Bighead sculpin
Batrachocottus baicalensis
FISH SPECIES
Freshwater Fish
Freshwater fish spend all or part of their lives in rivers, lakes, streams and wetlands. The label describes an environment, not one branch of the fish family tree, so freshwater species include many unrelated shapes and lineages.
FISH ATLAS / FIELD GUIDEFreshwater FishIN THIS CHAPTER01 / Characteristics02 / Lifestyle03 / Species04 / Field notes
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01 / NATURAL HISTORY
Characteristics
Freshwater habitats contain far less salt than seawater and can change quickly with seasons, floods and drought. Fish living there use many different strategies, from streamlined bodies for current to barbels that help find food near the bottom.
- 01River fish
- 02Lake fish
- 03Stream fish
02 / LIFESTYLE
Lifestyle
Life in freshwater follows the movement of water and food. Some fish hold position in a current and intercept drifting prey; others search plants or sediment for a meal. Changes in flow and water level can open feeding grounds or trigger movements toward spawning areas. These behaviors reflect how fish balance hydrodynamic energy expenditure against food intake.
OBSERVATION INDEX
- Holding position in a current
- Feeding among plants or sediment
- Movement with changing water levels
03 / SPECIES
Representative species
Discover representative species illustrating the ecological diversity, morphologies and adaptations of this group.
Bighead sculpin
Catostomidae
Bigmouth buffalo
Ictiobus cyprinellus
Cyprinidae
Bigmouth chub
Nocomis platyrhynchus
Galaxiidae
Bignose galaxias
Galaxias macronasus
Percidae
Bigscale Logperch
Percina macrolepida
Dorosomatidae
Bigscale pellonuline
Microthrissa congica
Cyprinodontidae
Bigscale Pupfish
Cyprinodon macrolepis
Cyprinidae
Bigspot barb
Barbodes dunckeri
Bryconidae
Bigtooth Brycon
Brycon dentex
Potamotrygonidae
Bigtooth river stingray
Potamotrygon henlei
Cyprinidae
Biharian barbel
Barbus biharicus
Cyprinidae
Bihorned barbel
Tariqilabeo bicornis
Cyprinidae
Bilobed-lip schizothoracin
Ptychobarbus kaznakovi
Cyprinidae
Binni
Mesopotamichthys sharpeyi
Osphronemidae
Bintan Licorice Gourami
Parosphromenus bintan
Botiidae
Birdi loach
Botia birdi
Loricariidae
Birindell's Whiptail Catfish
Loricaria birindellii
Percidae
Birmingham Darter
Etheostoma birminghamense
Poeciliidae
Bishop toothcarp
Brachyrhaphis episcopi
Poeciliidae
Bitschumbi lampeye
Lacustricola vitschumbaensis
Cyprinidae
bitterling
Rhodeus amarus
Cyprinidae
bitterling
Rhodeus amurensis
Cyprinidae
bitterling
Rhodeus sericeus
Cyprinidae
Bitungu
Barbodes truncatulus
04 / FIELD NOTES
A closer look
What makes a fish freshwater?
It is recorded from inland waters with low salinity for all or part of its life cycle.
Are all freshwater fish closely related?
No. Freshwater is a habitat category that includes many separate evolutionary groups.
Can freshwater fish survive in seawater?
Most cannot; without physiological adaptations to excrete excess salt, their cells rapidly lose water through osmosis and dehydrate in hypertonic seawater.